Stable 2,3,3,3-tetrafluoropropene composition

ABSTRACT

A stable composition (CS) including at least x wt.-% 2,3,3,3-tetrafluoropropene (99.8 ÿ x&lt;100), at most y wt.-% unsaturated compound(s) (Ia) (0&lt;y ÿ 0.2) selected from among 3,3,3-trifluoropropene (HFO-1243zf) and the positional isomers of 2,3,3,3-tetrafluoropropene, such as 1,3,3,3-tetrafluoropropene (isomers Z and E) and 1,1,2,3-tetrafluoropropene, and, optionally, at most 500 ppm of 3,3,3-trifluoropropyne and/or at most 200 ppm 1,1,1,2,3-pentafluoropropene (HFO-1225ye).

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.14/990,159, now U.S. Pat. No. 10,119,055, filed on Jan. 7, 2016, whichis a divisional of U.S. application Ser. No. 13/808,326, filed on Jan.1, 2013, now abandoned, which is U.S. national stage application ofInternational Application No. PCT/FR2011/051406, filed on Jun. 20, 2011,which claims the benefit of U.S. Provisional Application No. 61/364,539,filed on Jul. 15, 2010, and which claims the benefit of FrenchApplication No. 1055628, filed on Jul. 9, 2010. The entire contents ofeach of U.S. application Ser. No. 14/990,159, U.S. application Ser. No.13/808,326, International Application No. PCT/FR2011/051406, U.S.Provisional Application No. 61/364,539, and French Application No.1055628 are hereby incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a stable composition including2,3,3,3-tetrafluoropropene capable of being used in refrigeration andair conditioning.

BACKGROUND

The problems presented by substances which deplete the atmospheric ozonelayer were dealt with at Montreal, where the protocol was signedimposing a reduction on the production and use of chlorofluorocarbons(CFCs). This protocol has formed the subject of amendments which haverequired the abandoning of CFCs and have extended regulation to otherproducts, including hydrochlorofluorocarbons (HCFCs).

The refrigeration and air conditioning industries have invested a greatdeal in the replacement of these refrigerants and it is because of thisthat hydrofluorocarbons (HFCs) have been marketed.

In the motor vehicle industry, the air conditioning systems ofcommercial vehicles have been changed in many countries from arefrigerant comprising chlorofluorocarbon (CFC-12) to that ofhydrofluorocarbon (1,1,1,2-tetrafluoroethane: HFC-134a), which is lessharmful to the ozone layer. However, from the viewpoint of theobjectives set by the Kyoto protocol, HFC-134a (GWP=1430) is regarded ashaving a high heating power. The contribution to the greenhouse effectof a refrigerant is quantified by a criterion, the GWP (Global WarmingPotential), which summarizes the heating power by taking a referencevalue of 1 for carbon dioxide.

Hydrofluoroolefins (HFOs) have a low heating power and thus meet theobjectives set by the Kyoto protocol. The document JP 4-110388 discloses2,3,3,3-tetrafluoropropene (HFO-1234yf) as heat transfer agent inrefrigeration, air conditioning and heat pumps.

In addition to having good properties as a heat transfer agent, in orderfor a refrigerant to be accepted commercially, it must in particular bethermally stable and be compatible with lubricants. This is because itis highly desirable for the refrigerant to be compatible with alubricant used in the compressor present in the majority ofrefrigeration systems. This refrigerant and lubricant combination isimportant for the use and the effectiveness of the refrigeration system;in particular, the lubricant has to be sufficiently soluble in therefrigerant throughout the operating temperature range.

According to the document WO 2008/042066, as fluoroolefins are capableof decomposing on contact with moisture, oxygen or other compounds whenthey are used as refrigerant, possibly at high temperature, it isrecommended to stabilize them with at least one amine.

Other stabilizing agents, such as benzophenone derivatives, lactones andsome phosphorus-comprising compounds, have also been proposed forstabilizing fluoroolefins (WO 2008/027596, WO 2008/027516 and WO2008/027515).

Furthermore, the document EP 2 149 543 describes a process for thepurification of 1,1,1,2,3-pentafluoropropane, a starting material in themanufacture of HFO-1234yf, in order to obtain a product having a1,1,1,2,3-pentafluoropropene (HFO-1225ye) content of less than 500 ppmand a trifluoropropyne content of less than 50 ppm.

DETAILED DESCRIPTION

The Applicant Company has now developed a 2,3,3,3-tetrafluoropropenecomposition which makes it possible to improve the thermal stabilitywhen it is used in refrigeration systems.

A subject-matter of the present invention is thus a stable composition(SC) comprising at least x % by weight of 2,3,3,3-tetrafluoropropene(99.8≤x<100), at most y % by weight of unsaturated compound(s) (Ia)(0<y≤0.2) chosen from 3,3,3-trifluoropropene (HFO-1243zf) and thepositional isomers of 2,3,3,3-tetrafluoropropene, such as1,3,3,3-tetrafluoropropene (Z and E isomers) and1,1,2,3-tetrafluoropropene, and optionally at most 500 ppm of3,3,3-trifluoropropyne and/or at most 200 ppm of1,1,1,2,3-pentafluoropropene (HFO-1225ye).

The stable composition according to the present invention canadditionally comprise at least one of the compounds (Ib) chosen from1,1,1,2-tetrafluoropropane (HFC-254eb), 1,1,1,2,3-pentafluoropropane(HFC-245eb), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2-trifluoroethane(HFC-143), 1,1,1,2,3,3-hexafluoropropane, hexafluoropropene,cyclohexafluoropropene and 1,1,1,3,3-pentafluoropropene (HFO-1225zc).

The combined compounds (Ib) present in the composition according to thepresent invention represent at most 500 ppm.

Preferably, the SC composition comprises at least 99.85% by weight of2,3,3,3-tetrafluoropropene, at most y % by weight of unsaturatedcompound(s) (Ia) (0<y≤0.15) chosen from 3,3,3-trifluoropropene(HFO-1243zf) and the positional isomers of 2,3,3,3-tetrafluoropropene,such as 1,3,3,3-tetrafluoropropene (Z and E isomers) and1,1,2,3-tetrafluoropropene, and optionally at most 250 ppm of3,3,3-trifluoropropyne and/or at most 50 ppm of1,1,1,2,3-pentafluoropropene (HFO-1225ye).

The SC composition which is particularly preferred comprises at least99.9% by weight of 2,3,3,3-tetrafluoropropene, at most y % by weight ofunsaturated compound(s) (Ia) (0<y≤0.1) chosen from3,3,3-trifluoropropene (HFO-1243zf) and the positional isomers of2,3,3,3-tetrafluoropropene, such as 1,3,3,3-tetrafluoropropene (Z and Eisomers) and 1,1,2,3-tetrafluoropropene, and optionally at most 200 ppmof 3,3,3-trifluoropropyne and/or at most 5 ppm of1,1,1,2,3-pentafluoropropene (HFO-1225ye).

According to a preferred embodiment of the invention, the SC compositioncomprises from 99.85 to 99.98% by weight of 2,3,3,3-tetrafluoropropene,from 0.02 to 0.15% by weight of unsaturated compound(s) (Ia) chosen from3,3,3-trifluoropropene (HFO-1243zf) and the positional isomers of2,3,3,3-tetrafluoropropene, such as 1,3,3,3-tetrafluoropropene (Z and Eisomers) and 1,1,2,3-tetrafluoropropene, and optionally at most 200 ppmof 3,3,3-trifluoropropyne and/or at most 5 ppm of1,1,1,2,3-pentafluoropropene (HFO-1225ye) and/or at most 400 ppm ofcompounds (Ib).

The stable composition according to the invention exhibits the advantageof being able to be obtained directly by a process for the manufactureof 2,3,3,3-tetrafluoropropene, optionally after at least one separationstage.

Another subject-matter of the present invention is2,3,3,3-tetrafluoropropene which has a purity of greater than or equalto 99.8% by weight and less than 100% by weight and which comprises atmost 0.2% by weight of unsaturated compounds (Ia), optionally at most500 ppm of 3,3,3-trifluoropropyne and/or at most 200 ppm of1,1,1,2,3-pentafluoropropene and/or at most 500 ppm of compounds (Ib).

An additional subject-matter of the present invention is2,3,3,3-tetrafluoropropene which has a purity of greater than or equalto 99.9% by weight and less than 100% by weight and which comprises atmost 0.1% by weight of unsaturated compounds (Ia), optionally at most200 ppm of 3,3,3-trifluoropropyne and/or at most 5 ppm of1,1,1,2,3-pentafluoropropene and/or at most 500 ppm of compounds (Ib).

2,3,3,3-Tetrafluoropropene can be obtained from hexafluoropropene (HFP)in at least 4 reaction stages:—(i) hydrogenation of HFP in the presenceof a hydrogenation catalyst in a solid phase to give1,1,1,2,3,3-hexafluoropropane; (ii) dehydrofluorination of the1,1,1,2,3,3-hexafluoropropane obtained in stage (i) in the liquid phaseusing an alkali metal hydroxide or in the gas phase in the presence of adehydrohalogenation catalyst to give 1,1,1,2,3-pentafluoropropene; (iii)hydrogenation of the HFO-1225ye obtained in (ii) in the presence of ahydrogenation catalyst in the solid phase to give1,1,1,2,3-pentafluoropropane; (iv) dehydrofluorination of the HFC-245ebobtained in stage (iii) in the liquid phase using an alkali metalhydroxide or in the gas phase in the presence of a dehydrohalogenationcatalyst to give 2,3,3,3-tetrafluoropropene.

2,3,3,3-Tetrafluoropropene can be obtained from hexafluoropropene (HFP)in at least 2 reaction stages:—(i) hydrogenation of HFP in the presenceof a hydrogenation catalyst in the solid phase to give1,1,1,2,3-pentafluoropropane; (ii) dehydrofluorination of the HFC-245ebobtained in stage (i) in the liquid phase using an alkali metalhydroxide or in the gas phase in the presence of a dehydrohalogenationcatalyst to give 2,3,3,3-tetrafluoropropene.

The 2,3,3,3-tetrafluoropropene according to the present invention can beobtained from HFP according to a process as described above after apurification of the HFC-245eb and/or after purification of the2,3,3,3-tetrafluoropropene.

Thus, the HFC-245eb, prior to the dehydrofluorination stage, is, forexample, purified by distillation at an absolute pressure of 6 bar andat a column bottom temperature of 80° C. and a top temperature of 50° C.with approximately 30 theoretical plates and a reflux ratio ofapproximately 37.

After the final dehydrofluorination stage, the HFO-1234yf is subjectedto double distillation. The first distillation is carried out at anabsolute pressure of approximately 13 bar, a column bottom temperatureof approximately 60° C. and a top temperature of approximately 40° C.and with approximately 35 theoretical plates and a reflux ratio ofapproximately 500. The second distillation is carried out at an absolutepressure of approximately 11 bar, a column bottom temperature ofapproximately 105° C., and a top temperature of approximately 44° C. andwith approximately 30 theoretical plates at a reflux ratio ofapproximately 4.

The 2,3,3,3-tetrafluoropropene can also be obtained from1,1,1-trifluoro-2-chloropropene by hydrofluorination in the liquid orgas phase in the presence of a fluorination catalyst. The2,3,3,3-tetrafluoropropene thus obtained can be purified to give the2,3,3,3-tetrafluoropropene according to the present invention.

The compositions according to the present invention are capable of beingused as heat transfer agent in stationary or motor-vehicle airconditioning, refrigeration and heat pumps.

Another subject-matter of the present invention is the compositions asdescribed above in combination with a lubricant.

Mention may in particular be made, as lubricant, of polyol esters(POEs), polyalkylene glycols (PAGs), polyalkylene glycol esters andpolyvinyl ethers (PVEs).

The PAG lubricants are in the oxyalkylene homo- or copolymer form. Thepreferred PAGs are homopolymers composed of oxypropylene groups with aviscosity of 10 to 200 centistokes at 40° C., advantageously between 30and 80 centistokes. The hydroxyl groups at the ends of the oxyalkylenehomo- or copolymer chains can be more or less replaced by—O—C_(n)H_(2n+1) groups where n=1 to 10; the group with n=1 beingpreferred. The PAGs which may be suitable are those having hydroxylgroups for each ending or —O—C_(n)H_(2n+1) groups.

Mention may in particular be made, as POEs, of esters of carboxylicacids having a linear or branched carbon chain of 2 to 15 atoms and ofpolyols having a neopentyl backbone, such as neopentyl glycol,trimethylolpropane, pentaerythritol and dipentaerythritol;pentaerythritol is the preferred polyol. Esters of carboxylic acidshaving a carbon chain of 4 to 9 atoms are preferred.

Mention may in particular be made, as carboxylic acid of 4 to 9 carbonatoms, of n-pentanoic acid, n-hexanoic acid, n-heptanoic acid,n-octanoic acid, 2-ethylhexanoic acid, 2,2-dimethylpentanoic acid,3,5,5-trimethylhexanoic acid, adipic acid and succinic acid.

Some alcohol functional groups are not esterified; however, theproportion remains low.

The POE oils selected can comprise between 0 and 5 relative mol % ofCH₂—OH units with respect to the —CH₂—O—(C═O)— units.

The preferred POE lubricants are those having a viscosity of 1 to 1000centistokes (cSt) at 40° C., preferably of 10 to 200 cSt andadvantageously of 30 to 80 cSt.

EXPERIMENTAL PART

The thermal stability trials are carried out according to StandardASHRAE 97-2007: “sealed glass tube method to test the chemical stabilityof materials for use within refrigerant systems”.

The test conditions are as follows:

Weight of fluid: 2.2 g

Weight of lubricant: 5 g

Temperature: 200° C.

Duration: 14 days

Lengths of steel are introduced into tubes.

The length of steel and the lubricant are introduced into a 42.2 mlglass tube. The tube is subsequently evacuated under vacuum and then thefluid F is added thereto. The tube is then welded in order to close itand placed in an oven at 200° C. for 14 days.

At the end of the test, various analyses are carried out:

-   -   the gas phase is recovered in order to be analyzed by gas        chromatography: the main impurities were identified by GC/MS        (coupled gas chromatography/mass spectrometry). The impurities        coming from the fluid F and those coming from the lubricant can        thus be combined.    -   the length of steel is weighed (measurement of the rate of        corrosion) and observed under a microscope.    -   the lubricant is analyzed: color (by spectrocolorimetry, Labomat        DR Lange LICO220 model MLG131), water content (by Karl Fischer        coulometry, Mettler DL37) and acid number (by quantitative        determination with 0.01N methanolic potassium hydroxide).

The lubricant used in the tests is a commercial PAG oil: PAG ND8.

The fluid used for these trials comprises essentially HFO-1234yf (atleast 99.9% by weight) and then 300 ppm of HFO-1243zf, 500 ppm of EHFO-1234ze and 300 ppm of HFO-1243zf+500 ppm of E HFO-1234ze arerespectively added to the fluid.

Content of ppm ppm ppm ppm E HFO- — — 500 500 1234ze added HFO- — 300300 1243zf added Byproducts in the gas phase: from the 600 ppm 600 ppm900 ppm 900 ppm HFO-1234yf from the oil 1.4% 1.4% 1.4% 1.4% Rate of <5μm/year <5 μm/year <5 μm/year <5 μm/year corrosion Analysis of the oil:color 10 Gardner 9 Gardner 8.5 Gardner 9 Gardner water content 300 ppm300 ppm 250 ppm 300 ppm acid number 5.2 mg 5.2 mg 4.5 mg 5.2 mg KOH/gKOH/g KOH/g KOH/g

The examples show that the presence of the compounds (Ia) is not harmfulto the thermal stability, either of the HFO-1234yf composition or of thelubricant, and in some cases improves it.

The invention claimed is:
 1. A stable composition comprising 99.8 x<100%by weight of 2,3,3,3-tetrafluoropropene, 0<y≤0.15% by weight of thepositional isomers of 2,3,3,3-tetrafluoropropene, 3,3,3-trifluoropropene(HFO-1243zf), and 3,3,3-trifluoropropyne and/or1,1,1,2,3-pentafluoropropene (HFO-1225ye), wherein the compositioncontains at most 500 ppm of 3,3,3-trifluoropropyne and/or at most 200ppm of 1,1,1,2,3-pentafluoropropene (HFO-1225ye).
 2. The stablecomposition according to claim 1, further comprising at least onecompound (Ib) selected from the group consisting of1,1,1,2-tetrafluoropropane (HFC-254eb), 1,1,1,2,3-pentafluoropropane(HFC-245eb), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2-trifluoroethane(HFC-143), 1,1,1,2,3,3-hexafluoropropane, hexafluoropropene,cyclohexafluoropropene, 1,1,1,3,3-pentafluoropropene (HFO-1225zc), andmixtures thereof.
 3. The stable composition according to claim 2,wherein the compound(s) (Ib) represent(s) at most 500 ppm of the stablecomposition.
 4. The stable composition according to claim 1, wherein thestable composition comprises at least 99.85% by weight of2,3,3,3-tetrafluoropropene, 0<y≤0.1% by weight of the positional isomersof 2,3,3,3-tetrafluoropropene, 3,3,3-trifluoropropene (HFO-1243zf), and3,3,3-trifluoropropyne and/or 1,1,1,2,3-pentafluoropropene (HFO-1225ye),wherein the composition contains at most 250 ppm of3,3,3-trifluoropropyne and/or at most 50 ppm of1,1,1,2,3-pentafluoropropene (HFO-1225ye).
 5. The stable compositionaccording to claim 1, wherein the stable composition comprises at least99.9% by weight of 2,3,3,3-tetrafluoropropene, 0<y≤0.05% by weight ofthe positional isomers of 2,3,3,3-tetrafluoropropene,3,3,3-trifluoropropene (HFO-1243zf), and 3,3,3-trifluoropropyne and/or1,1,1,2,3-pentafluoropropene (HFO-1225ye), wherein the compositioncontains at most 200 ppm of 3,3,3-trifluoropropyne and/or at most 5 ppmof 1,1,1,2,3-pentafluoropropene (HFO-1225ye).
 6. The stable compositionaccording to claim 1, wherein the stable composition comprises from99.85 to 99.98% by weight of 2,3,3,3-tetrafluoropropene, from 0<y≤0.1%by weight of the positional isomers of 2,3,3,3-tetrafluoropropene,3,3,3-trifluoropropene (HFO-1243zf), and 3,3,3-trifluoropropyne and/or1,1,1,2,3-pentafluoropropene (HFO-1225ye) and/or compounds (Ib), whereinthe composition contains at most 200 ppm of 3,3,3-trifluoropropyneand/or at most 5 ppm of 1,1,1,2,3-pentafluoropropene (HFO-1225ye) and/orat most 400 ppm of compounds (Ib).
 7. The stable composition accordingto claim 1, wherein the stable composition is configured for use as aheat transfer agent in stationary or motor-vehicle air conditioning,refrigeration and heat pumps.
 8. The stable composition according toclaim 1, wherein the stable composition further comprises a lubricant.9. The stable composition according to claim 8, wherein the lubricant isselected from the group consisting of polyol esters (POEs), polyalkyleneglycols (PAGs), polyalkylene glycol esters and polyvinyl ethers (PVEs).10. The stable composition according to claim 1, wherein the positionalisomers of 2,3,3,3-tetrafluoropropene compriseE-1,3,3,3-tetrafluoropropene, Z-1,3,3,3-tetrafluoropropene, and1,1,2,3-tetrafluoropropene.
 11. 2,3,3,3-Tetrafluoropropene which has apurity of greater than or equal to 99.8% by weight and less than 100% byweight and which comprises 3,3,3-trifluoropropene (HFO-1243zf), at most0.15% by weight of the positional isomers of 2,3,3,3-tetrafluoropropene,and 3,3,3-trifluoropropyne and/or 1,1,1,2,3-pentafluoropropene and/orcompounds (Ib), wherein the 2,3,3,3-tetrafluoropropene contains at most500 ppm of 3,3,3-trifluoropropyne and/or at most 200 ppm of1,1,1,2,3-pentafluoropropene and/or at most 500 ppm of compounds (Ib).12. 2,3,3,3-Tetrafluoropropene according to claim 11, characterized by apurity of greater than or equal to 99.9% by weight and less than 100% byweight and comprising 3,3,3-trifluoropropene (HFO-1243zf), at most 0.05%by weight of the positional isomers of 2,3,3,3-tetrafluoropropene, and3,3,3-trifluoropropyne and/or 1,1,1,2,3-pentafluoropropene and/orcompounds (Ib), wherein the 2,3,3,3-tetrafluoropropene contains at most200 ppm of 3,3,3-trifluoropropyne and/or at most 5 ppm of1,1,1,2,3-pentafluoropropene and/or at most 500 ppm of compounds (Ib).13. 2,3,3,3-Tetrafluoropropene according to claim 11, wherein thepositional isomers of 2,3,3,3-tetrafluoropropene compriseE-1,3,3,3-tetrafluoropropene, and Z-1,3,3,3-tetrafluoropropene, and1,1,2,3-tetrafluoropropene.